Chokes are widely used in electronics to block higher-frequency alternating current (AC) in an electrical circuit, while allowing lower frequency or DC current to pass. A choke can generally include a coil of insulated wire, which can be wound on a magnetic core. In operation, the impedance of the choke generally increases with frequency. As such, the low electrical resistance can allow both AC and DC current to pass with relatively low power loss, but can limit or reduce the amount of AC current passing therethrough due to the reactance of the coil.
Certain types of chokes, such as common-mode choke, can be useful for prevention of electromagnetic interference (EMI) and radio frequency interference (RFI), for example from power supply lines, and for protection of electronic equipment sensitive to AC current noise. Common-mode chokes can include two coils wound on a core. In operation, the two coils can pass equal but opposite differential currents while blocking common-mode currents. However, there remains a continued need for improved chokes and techniques to reduce or prevent damage to electronic equipment sensitive to AC current noise.